JPWO2011102317A1 - Monitoring system, apparatus and method - Google Patents

Abstract

Provided is a monitoring system capable of realizing priority control in consideration of a wide band limitation. A priority order / filter type selection processing unit 37 of the network interconnection device 11 that connects the local network 14 and the wide area network 10 includes a transmission data selection processing unit 38 based on the priority definition of transmission data according to the event status, and an event status. In addition, the data compression method corresponding to the wide area network communication status is selected, and the filtering processing unit 33 is selectively controlled to reduce the communication band in the wide area network.

Description

  The present invention relates to a monitoring system, and more particularly to a monitoring technique for performing priority control in consideration of bandwidth limitation of a broadband network.

  In recent years, there is an increasing demand for remote monitoring of equipment monitoring and maintenance, such as boilers and thermal turbines, and energy consumption monitoring from the center side away from the site. It is ideal that all the data of sensors and surveillance cameras installed at the end of such a monitoring system is sucked up to the center side, but as the number of them increases, from the relationship of traffic capacity that can be transmitted from the network, It has become difficult to constantly download all data to the center.

  In order to cope with such a current situation, for example, in Patent Document 1, a technique for controlling the priority of transfer / display of image data from a camera based on priority information obtained from communication between a mobile node and a fixed node. Is disclosed.

JP 2009-171471 A

The following factors can be considered as the factors of difficulty in downloading all the data described above.
-Since the number of high-data-rate terminals such as camera moving images has increased, the total capacity of data generated in the network is the traffic capacity that can be transmitted over the network (usually about 100 M to 10 Gbps with Ethernet (registered trademark)) Will be exceeded.
・ Due to the total multiplexing effect, the difference between the average value and the maximum value of the total traffic volume is large, and overdesigning the network under worst conditions will result in overspec.
・ When using public networks such as the Internet, the amount of traffic generated under the same network cannot be predicted.
・ Especially when using wireless communication, the transmission capacity varies depending on radio wave propagation conditions.

  Furthermore, even if the network traffic capacity is sufficient, there is a need to minimize the communication cost when using a pay network (especially pay-per-use).

  As mentioned above, because the network traffic capacity is insufficient or fluctuates, it is not possible to always list all the data in the center. For example, for data with high priority due to QoS (Quality of Service) bandwidth guarantee, always use the bandwidth. A combination of the securing method and the sending method as much as possible within the range that can be sent by the best effort communication is conceivable. Further, when the priority changes depending on the status of abnormality information to be monitored, the presence / absence of an alert, etc., the priority order of data for guaranteeing the QoS bandwidth may be changed.

  However, if the data rate is low, such as a temperature sensor, but the information that you want to send reliably at regular intervals and the data rate that is high, such as a surveillance camera, but low priority are usually mixed, QoS If the priority of surveillance camera data is raised only when an alarm is detected while the guaranteed bandwidth remains constant, the QoS guaranteed bandwidth is monopolized by the camera data and sensor data cannot be sent, and the QoS guaranteed bandwidth is expanded only when an alarm is detected. In such a case, depending on the traffic state of the network at that time, there may be a situation in which the necessary QoS guaranteed bandwidth cannot always be secured.

  An object of the present invention is to solve the above-described various problems and provide a monitoring system capable of realizing priority control in consideration of network bandwidth limitation.

  Another object of the present invention is to mix information that the data rate is low but that is surely sent at regular intervals, and information that is high in data rate but low in priority at normal times, and has insufficient network traffic capacity. Another object of the present invention is to provide a communication control apparatus and method for reducing the amount of data to be collected to the management center while maintaining the performance as a monitoring system when all data cannot be listed in the management center at all times due to fluctuations. .

  In order to achieve the above object, the present invention is a monitoring system using a network interconnection device that connects a first network to which a plurality of communication terminals are connected and a second network to which a management center is connected. Then, the network interconnection device selects the transmission data to the upper node such as the management center of the second network based on the priority order of the transmission data according to the event status of the plurality of communication terminals, and the event status and the communication status of the network A monitoring system for selecting a data compression method for transmission data according to the data is provided.

  In order to achieve the above object, according to the present invention, communication control is performed so as to receive data from a plurality of communication terminals via the first network and transmit the data to the management center via the second network. The apparatus includes a communication unit that communicates with each of the first network and the second network, a processing unit, and a storage unit. The processing unit receives data from a plurality of communication terminals via the communication unit. The event status is extracted by filtering processing, the communication status of the second network is estimated based on the received data from the management center received via the communication unit, and the degree of compression of data to be transmitted is determined according to the communication status. Provided is a communication control device that selects and determines a priority order of data to be transmitted and a compression method based on an event status and a compression degree.

  Furthermore, in order to achieve the above object, the present invention includes a communication unit, a processing unit, and a storage unit, receives data from a plurality of communication terminals via the first network, A communication control method for a communication device that transmits to a management center via a network, wherein the processing unit extracts an event status based on data from a plurality of communication terminals via the communication unit, and receives the event status via the communication unit Based on the data received from the management center, the communication status of the network is estimated, the compression level of the data to be transmitted is selected according to the communication status, and the priority order of the data to be transmitted is determined based on the event status and the compression level. Provided is a communication control method for determining a compression method.

  According to the present invention, even when all the data generated in the first network cannot always be sent through the second network, the amount of data sent to the second network can be reduced without degrading the performance of the monitoring system. Can be reduced. Furthermore, even if a pay network is used, the communication cost can be suppressed.

1 is an overall configuration diagram of a communication system according to Embodiment 1 of the present invention. 1 is a diagram illustrating a configuration example of a local network in Embodiment 1. FIG. It is a figure which shows one Example of the network interconnection apparatus based on Example 1. FIG. FIG. 6 is a diagram illustrating a processing flow of a priority order / filter type selection processing unit according to the first embodiment. It is a figure which shows an example of the table for every status based on Example 1. FIG. It is a figure which shows an example of the compression degree calculation table based on Example 1. FIG. 6 is a diagram illustrating an example of components of a status table according to Embodiment 1. FIG. It is a figure which shows another example of the component of the table for status based on Example 1. FIG. It is a figure for demonstrating the effect of the monitoring system of Example 1. FIG. It is a figure explaining the communication flow for the communication condition judgment of the wide area network based on Example 1. FIG. It is a figure explaining the communication flow for the communication condition judgment of the wide area network based on Example 1. FIG. It is a figure explaining the communication flow for the communication condition judgment of the wide area network based on Example 1. FIG. It is a figure which shows the example of 1 structure of the network interconnection apparatus based on Example 1. FIG. 1 is a diagram illustrating a configuration example of a communication terminal according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration example of a management center according to Embodiment 1. FIG. It is a figure which shows the graph of probability distribution of the statistical data of a time difference based on Example 1. FIG. It is a whole block diagram of the communication system which concerns on Example 3 of this invention. It is a whole block diagram of the communication system which concerns on Example 4 of this invention. FIG. 10 is a diagram illustrating an example of components of a status table according to the fourth embodiment. FIG. 10 is a diagram illustrating another example of components of a status table according to the fourth embodiment. It is a figure which shows an example of the content and format of the information which are transmitted to the network interconnection apparatus from a communication terminal based on Example 1 and Example 4. FIG. It is a figure which shows another example of an example of the component of the table for status shown to FIG. 6A, 6B. It is a figure which shows another example of an example of the component of the table for status shown to FIG. 6A, 6B.

  Hereinafter, various embodiments of the present invention will be described with reference to the drawings. In the specification of the present application, a configuration realized by various software executed by a central processing unit (CPU) is expressed as “program”, “processing unit”, “module”, or “unit”. .

  FIG. 1 shows an overall configuration diagram of a communication system according to the first embodiment that can realize various types of monitoring. In the figure, reference numerals 10 and 14 denote a wide area network called a WAN (Wide Area Network) and a local network called a LAN (Local Area Network), respectively, and 11 denotes a network interconnection apparatus for interconnecting them. is there. A plurality of communication terminals 12 such as various sensors such as a temperature sensor and a monitoring camera are connected to the local network 14 functioning as the first network, and the upper level node is connected to the wide area network 10 functioning as the second network. The management center 13 is connected. In this system configuration which is a two-layer model, the network interconnection device 11 functions as an edge node of each network. Needless to say, the first network and the second network are not limited to the illustrated LAN and WAN.

  FIG. 2 shows an example of a more specific configuration of the local network 14 functioning as the first network of this embodiment. In the figure, reference numeral 20 denotes a monitoring device to be monitored, and reference numerals 21 to 25 denote a sensor 1, a sensor 2, a sensor 3, a monitoring camera 4, and a monitoring camera 5, which are the communication terminals 12 of FIG. In the local network 14 shown in the figure, various sensing data such as the operating environment related to the monitoring device 20 and monitoring video data are transmitted from the sensor and the monitoring camera to the wide area network 14 functioning as the second network via the network interconnection device 11. The

  That is, in the monitoring system of this embodiment shown in FIGS. 1 and 2, the sensors 21 to 23 and the monitoring cameras 24 and 25 are arranged around the monitoring device 20, and once function as an edge node of the local network 14. After the data is collected in the interconnection device 11, the data is further collected in the management center 13 via the wide area network 10.

  In the monitoring system of the present embodiment, as a specific example, the sensing data of the sensors 21 to 23 is 1 kbps without compression, and the minimum is 0. 0 by filtering processing such as averaging and feature extraction described in detail later. It can be compressed to 2 kbps. The data from the cameras 24 and 25 can be configured to be selectable from five levels of 4k, 16k, 32k, 64k, and 128 kbps according to the image quality per unit, but it goes without saying that the present invention is not limited to these. Yes.

  The contents and format (packet format) of information sent from the communication terminal 12 to the network interconnection device will be described with reference to FIG. The communication terminal 12 sends header information 180 and sensing information 181 including various sensing data and images input from a sensor or a monitoring camera connected to the terminal. In the header information 180, a terminal type 182 indicating the type of the communication terminal and the connected device (sensor, monitoring camera, etc.), a terminal ID 183 for distinguishing a plurality of communication terminals, and sensing information when acquired Time information 184 and the like are included. In this embodiment, the terminal type is divided into two types, “sensor” and “monitoring camera”, and the terminal ID is 1 to 5. The terminal ID can be assigned with a serial number regardless of whether the terminal type is “sensor” or “monitoring camera” as in the present embodiment, and is divided into “sensor 1” and “monitoring camera 1” for each terminal type. It can also be attached.

  First, an example of the internal configuration of the network interconnection device 11, the communication terminal 12, and the management center 13 in the overall system configuration of the present embodiment shown in FIG. 1 will be described with reference to FIGS. To do.

  FIG. 11 shows an embodiment of the network interconnection device 11. In FIG. 1, a network interconnection device 11 includes a local network 14 and a local network communication interface (I / F) 111 connected to the wide area network 10 and a wide area network communication I / F 116, and an internal bus 117 connecting them. A central processing unit (CPU) 112 serving as a connected processing unit, a hardware accelerator 115 serving as a processing unit, a calculation memory 114 serving as a storage unit, and a storage unit storing a program executed by the CPU 112 It is composed of a program storage memory 113. Various tables described in detail may be stored and stored in either the calculation memory 114 or the program storage memory 113 constituting the storage unit. Here, the hardware accelerator 115 refers to a part that replaces a part of software operation such as the filtering processing unit 33 executed by the CPU 112 with a hardware circuit, and speeds up the operation as the filtering processing unit 1151. For example, an FFT operation, an error correction decoding operation such as a turbo code, compression / decompression of an MPEG image, and the like, and a commercially available circuit IP of an FPGA (Field Programmable Gate Array) can be used. It is.

  Further, the program storage memory 113 includes each processing unit shown in FIG. 3, a filtering program 1131 corresponding to each table shown in FIGS. 5A and 5B, a local network data statistical program 1132, a priority order / filter type selection. A program 1133, a wide area network status promotion program 1136, a transmission data selection program 1137, a status table 1134, and a compression degree calculation table 1135 are stored. On the other hand, according to the execution status of each program, the calculation memory 114 includes, as its areas, a buffering area 1141, local network data statistical information 1142, wide area network status estimation information 1143, priority order / filter type selection information 1144. Is provided.

  FIG. 12 shows an embodiment of the communication terminal 12. In the figure, the communication terminal 12 includes the block elements shown in FIG. 12 in addition to the sensor function and camera function as the various communication terminals described above. That is, a local network communication I / F 121 connected to the local network 14 is provided, and the CPU 122, the arithmetic memory 124, and the program storage memory 123 are connected to the internal bus 127 connected thereto. Each communication terminal 12 uses these CPU 122, calculation memory 124, and program storage memory 123 to process data from each sensor function unit and camera function unit (not shown) and send them to the local network 14. To control.

  Also in this figure, the hardware accelerator 125 is partially replaced by the filtering processor 1251. The program storage memory 123 stores a filtering program 1231 and a local network data statistics program 1232. On the other hand, the computing memory 124 is provided with a buffering area 1241 and local network data statistical information 1242 as areas according to the execution status of each program.

  FIG. 13 shows an embodiment of the management center 13. In the figure, the management center 13 includes a wide area network communication I / F 136 connected to the wide area network 10, and a CPU 132, a hardware accelerator 135, an arithmetic memory 134, and a program storage area connected to an internal bus 137 connected thereto. The memory 133 is configured.

  Similarly, in the configuration shown in the figure, the hardware accelerator 135 is partially replaced by the filtering processing unit 1351. The program storage memory 133 stores a filtering program 1331 and a wide area network status promotion program 1332. On the other hand, the computing memory 134 is provided with a buffering area 1341 and wide-area network status estimation information 1342 as its area according to the execution status of each program.

  FIG. 3 is a diagram illustrating a configuration of the network interconnection apparatus 11 that functions as an edge node according to the first embodiment. In the figure, reference numerals 31 to 39 denote processing blocks realized by software executed by the processing unit of the network interconnection apparatus 11 or dedicated hardware realized by an FPGA, respectively. A processing unit, a filtering processing unit, a priority control unit, a local network data statistical processing unit, a priority order / filter type selection processing unit, a wide area network status estimation processing unit, a transmission data selection processing unit, and a wide area network communication processing unit are shown. The wide area network state estimation processing unit 36 realizes processing for periodically monitoring the communication state of the wide area network 10, that is, the average of the substantially transmittable rates.

  The local network communication processing unit 31 is a communication interface with the local network 14. The buffering processing unit 32 functions as a data buffer using a memory.

  The filtering processing unit 33 includes reversible processing such as compression processing of the header information 180 and irreversible processing such as quantization processing of the sensing information 181 among the information from the communication terminal described above with reference to FIG. The contents of the filtering processing of the filtering processing unit 33 can be read out as a filtering processing library created in advance in the device 11 which is an edge node, or distributed from a management center corresponding to a higher node.

  The reversible process includes a difference calculation process from a reference value of sensing information by a sensor, a process for generating a packet of a plurality of pieces of sensing information, a compression process of header information in accordance with a defined communication protocol (for example, specified in IETF standard RFC4944) Yes).

  On the other hand, as irreversible processes, unnecessary sensing information discarding process, sensing information average value calculation process, maximum / minimum value detection / determination process, abnormal value determination process, sampling thinning process in time direction, quantization process, And frame extraction processing of camera image information, image size change processing, feature extraction processing such as face detection and motion detection.

  Even when the irreversible processing is performed and the accuracy of the sensing information is lowered or the meaning is changed, the buffering processing unit 32 buffers the data before processing in the network interconnection device 11 as an edge node. Thus, when the data before processing is sent as it is or when it becomes necessary later, it is possible to access the device 11 which is the edge node from the upper node and confirm the data before processing.

  As shown in FIG. 3, the priority control unit 34 roughly provides the following three processes. That is, the local network data statistical processing unit 35, the wide area network status estimation processing unit 36, and the priority order / filter type selection processing unit 37. These processes can be realized by a software process executed by the CPU 132 for a program corresponding to each process stored in the program storage memory 133 of FIG. 11 described above.

  Here, the wide area network state estimation processing unit 36 estimates the communication state such as throughput and delay of the wide area network 10 used when the wide area network communication processing unit 39 sends the sensing information collected by the edge node to the upper node. The priority order / filter type selection processing unit 37 is notified.

  The wide area network 10 includes a closed network dedicated to the target system and an open network such as the Internet or a mobile phone network. When the amount of data (bandwidth) that can be selected is always guaranteed, There are cases where traffic changes from time to time and is not guaranteed. If the bandwidth is guaranteed, the broadband network state estimation processing unit 36 holds information on the guaranteed bandwidth at the time of setting. When the bandwidth fluctuates, TCP / IP (Transmission Control Protocol / Internet Protocol) window size information is used as reference information, and measurement packets including time information are periodically exchanged between the upper nodes of the edge node, For example, a transmission delay is calculated from the difference between the reception time of the measurement packet and the time information included in the packet.

  The local network data statistical processing unit 35 includes the throughput and delay of the local network 14 used when the edge node collects sensing information from the sensor, and what amount of priority data is included. The communication status is measured and notified to the priority order / filter type selection processing unit 37.

  In the priority order / filter type selection processing unit 37, the communication status (data amount that can be transmitted) notified from the wide area network status estimation processing unit 36 and the local network 14 notified from the local network data statistical processing unit 35. From the three inputs of the communication status (data amount and priority distribution to be transmitted) and post-processing data (abnormal value determination result, etc.) notified from the filtering processing unit 33, the data from which terminal is actually The filtering process (filtering condition) is determined in what form, and the order of transmission is determined. The priority order / filter type selection processing unit 37 notifies the transmission data selection processing unit 38 of the result including the determined filtering condition and transmission order.

  FIG. 4 is a diagram illustrating a processing flow of the priority order / filter type selection processing unit 37 of the priority control unit 34.

  An operation flow of an example of this determination method is shown in FIG. In FIG. 4, first, in the initial state (40), the event condition is detected (41) from the processed data notified from the filtering processing unit 33, for example, the abnormality determination result (41), and the event status of the local network is determined. (42) Note that the abnormality determination in the filtering processing unit 33 includes, as described in detail above, abnormal value determination based on a difference calculation result from a reference value of sensing information such as a temperature sensor and a microphone, face detection, motion detection, and the like. Software processing such as person detection based on feature extraction.

  Next, the status table describing the data compression method to be referred to is selected from the event status (43). Then, the compression rate is calculated from the ratio between the data amount desired to be sent and the data amount that can be sent, and the sending order and the filter type suitable for the compression rate are determined with reference to the selected status table (44). In this embodiment, the local network data statistical processing unit 35 performs local network state determination (45), and the wide area network state estimation processing unit 36 performs wide area state determination (46). Based on the state determination result, the compression degree corresponding to both network states is selected (47) from the compression degree calculation table described later, and the transmission order and the filter type are designated. It goes without saying that the filter type includes a compression method by software such as the sampling thinning process in the time direction, the quantization process, the frame thinning process of the camera image information, and the image size changing process.

  Next, using the configuration of the monitoring system of the present embodiment described above, specific examples of the priority control method in consideration of the network bandwidth limitation in the network interconnection device 11 are shown in FIGS. This will be described using 6B. The network interconnection device 11 sets a plurality of status tables that define priorities when sending data from each sensor and camera to the network, and is effective according to event conditions such as normal time and when an alarm of a sensor is detected. By switching the table to be used, a priority control method considering the bandwidth limitation is realized.

  FIG. 5A shows an example of event status conditions in this embodiment, that is, a table for each status and its components. In the figure, reference numerals 51, 52 and 53 denote tables for status A, status B and status C, respectively. The status C table 53 shown as an example includes a compression rate, a transmission order, and a filter type corresponding to the degree of compression as table components. The degree of compression has a value of 1 or more. As shown in the status C table 53, when the degree of compression is 1, the compression rate is 1.0, and there is no compression of the transmitted data. The sending order is defined to send in the order of α, β, γ. When the compression level is 1, for example, the data amount is 259 kbps, and the data amount is set to be reduced to 131 kbps, ----, 8.6 kbps, 4.6 kbps, corresponding to the increase in the compression rate.

  FIG. 5B shows an example of the compression degree calculation table 54 for calculating the compression degree based on the network state and the communication state in this embodiment. As can be seen from the figure, in the case of the present embodiment, compression levels 1 to 4 are selected based on the local network state on the vertical axis and the wide area network state on the horizontal axis. Based on the selected / determined compression degree, the corresponding compression degree in each event status table is selected / determined.

6A and 6B, as specific examples of statuses that are the event conditions shown in FIG. 5A, status tables that are used in the event conditions that occur when an abnormality occurs in the sensor 1 or the sensor 2, such as a sudden change in the temperature sensor detection temperature. An example was given. 6A, the status table 61 has compression degree, compression rate, transmission order, and filter type as table components, like the table 53 of FIG. 5A, and is illustrated corresponding to the compression degrees 1, 2, and 3, respectively. The compression ratio is 1.0, 0.6, 0.4.
Further, the sending order is such that the data of the sensor 1 in which an abnormality has occurred is sent first as shown for the sensors 1 to 3, the monitoring camera 4, and the alarms 1 to 3. Furthermore, as the filter type, no filter, only sending alarm detection result, etc. are selected as appropriate for sensors 1 to 3, and only the feature extraction results such as no thinning, image size change and thinning, and presence / absence of people are sent to the monitoring camera. Are appropriately selected. For example, at a degree of compression of 3, the alarm result of the sensor 1 in which an abnormality has occurred, the feature extraction result of the monitoring camera 4, and the alarm detection results of the other sensors 2 and 3 are sent out.

  Similarly, the status table 62 in FIG. 6B has compression ratios of 1.0, 0.6, and 0.3 corresponding to the compression degrees 1, 2, and 3, respectively, and the sending order is also as shown in the figure. It is determined. Further, the filter type is as shown in the figure. The difference from the status table 61 in FIG. 6A is that the sensors 1 and 2, the monitoring camera 5, and the monitoring camera 4 are switched in the sending order and filter type. This is because the sensor data related to the occurrence of abnormality is transmitted with the highest priority. That is, when the event status condition is abnormal, the data of the sensor that detected the abnormality is given the highest priority, followed by the data of the monitoring camera related to the degree of compression corresponding to the traffic situation of the network, or other sensors Data is given priority.

  It should be noted that the various tables shown in FIGS. 5A, 5B, 6A, and 6B are merely examples, and needless to say, other elements can be taken.

  As a modification of FIGS. 6A and B, FIGS. 19A and 19B are shown. FIGS. 19A and 19B are more specific examples of FIGS. 6A and 6B. In the section of the transmission order, in order to specify which terminal the data comes from, the terminal type 182 and the terminal ID 183 described above with reference to FIG. Is specified. The information on the terminal type and the terminal ID is included in the header information of the packet sent from the communication terminal 21. Data that is not specified in the sending order section (for example, the image of the monitoring camera 4 in FIG. 19A of this embodiment) is collected up to the network interconnection device 11 but is not sent to the management center 13. In the filter type section, the type of processing to be added by the filtering processing unit 33 is specified for the data specified in the transmission order section. For example, in the degree of compression 1, data is designated in the order of pre-process data of the sensor 1, pre-process data of the monitoring camera 5, pre-process data of the sensor 2, and pre-process data of the sensor 3. In the degree of compression 3, the transmission data is designated in the order of the alarm detection result (event status) of the sensor 1, the feature extraction result of the monitoring camera 5, the alarm detection result of the sensor 2, and the alarm detection result of the sensor 3.

  In this embodiment, the priority is determined, that is, the priority is determined, and the compression method of sensing data and surveillance camera data is selected in accordance with the transmittable bandwidth, regardless of the traffic state of the network. Data from all communication terminals can always be transmitted.

  An example of a communication flow for determining the network communication status in the monitoring system of the present embodiment will be described with reference to FIGS. 8, 14, 9, and 10. FIG. The communication flows of FIGS. 8, 9, and 10 correspond to whether the device that gives time or the device that determines the communication status of the network is the network interconnection device 11, the management center 13, or the communication terminal 12. Yes.

  First, in the communication flow shown in FIG. 8, when the communication terminal 12 on the monitoring system transmits a packet to the network interconnection device 11 via the local network 14, the device 11 is buffered by the buffering processing unit described above. Ring (81) is performed, and packet data to be transmitted is selected (82) from the buffered packet data. Subsequently, time information at the time of transmission is added to the header information of the selected packet (83), and the packet is transmitted to the management center 13 via the wide area network 10. The management center 13 records (84) the header information of the received packet together with the time information at the time of reception. FIG. 8 illustrates an example of the wide area transmission time and the wide area reception time.

  Then, the management center 13 sequentially transmits the time difference information and the like to the network interconnection device 11 as feedback information. The network interconnection apparatus 11 that has received this sequential feedback information accumulates feedback information of the time difference between the wide area reception time and the wide area transmission time, and can determine the communication status of the wide area network 10 by statistical processing. The statistical processing in the network interconnection device 11 will be described with reference to FIG. This statistical processing can be realized by software processing executed by the CPU 132 using the statistical processing program stored in the program storage memory 133 of FIG. 11 described above. This statistical processing program is included in the wide area network state estimation processing unit 37 having the configuration of the network interconnection device 11 shown in FIG.

  Reference numeral 141 in FIG. 14 is a graph showing the probability distribution of the time difference statistical data described above. The horizontal axis of the graph 141 in FIG. 14 represents the above-described time difference, and the vertical axis represents the occurrence probability distribution of the accumulated data delay amount (time difference). The statistical processing program determines the communication status depending on which of the “margin”, “normal”, and “congested” areas set in advance as threshold values the delay amount corresponding to the time difference at which the probability density is 142 at the maximum. As an index for this determination, not only the value when the probability density becomes maximum but also the value when the cumulative probability is larger than the predetermined value n percentage (cumulative probability> n%) may be used. Needless to say, the area division is not limited to the three areas shown in the figure, and can be divided more finely. In any case, such a statistical processing program itself is easily available.

  Next, the case of the processing flow shown in FIG. 9 will be described. The description will focus on differences from FIG. When the packet data selected from the network interconnection device 11 is transmitted, the management center 13 records the header information of the received packet together with the time information at the time of reception (84), and the time difference information based on this time information. The communication status of the wide area network 10 is determined (91). In the processing flow of FIG. 9, unlike FIG. 8, the management center 13 determines the communication status of the wide area network 10 based on statistical processing, and periodically feeds back the result to the packet transmission source network interconnection device 11. . Needless to say, this periodic feedback information is sent to the wide area network state estimation processing unit 37 of FIG. 3 described above.

  Next, the process flow shown in FIG. 10 will be described. In the case of this processing flow, when the communication terminal 12 generates a packet, time information is added to the header (101), and the packet is transmitted. The network interconnection device 11 records (102) the header information of the received packet together with the time information at the time of reception. Thereafter, through processing similar to the processing of FIGS. 8 and 9, the management center 13 records (103) the header information of the packet received from the device 11 together with the time information at the time of reception. In the case of this processing flow, the recorded time information includes the packet generation time and the local reception time in addition to the wide area transmission time and the wide area reception time. Here, it goes without saying that the local reception time is time information when the network interconnection device 11 receives a packet via the local network 14.

  These pieces of time information are transmitted to the network interconnection device 11 by successive feedback, and the device 11 determines the communication status of the local network 14 from the difference information between the local reception time and the packet generation time (104), and similarly the wide area The communication status of the network 10 is determined (85). As a modified example, the packet generation time and local reception time of a packet transmitted from the network interconnection device 11 to the management center 13 are accumulated in the device 11 and time difference statistics are stored using the accumulated data. Processing can also be performed to determine the communication status of the local network 14. In any case, it goes without saying that the local network data statistical processing unit 35 which is one of the configurations of the network interconnection device 11 shown in FIG. 3 performs this statistical processing.

  Next, the effect of the data transmission method of the first embodiment described in detail above will be described with reference to FIG. FIG. 7 shows a comparison between the conventional method not using the configuration of this embodiment and the method of this embodiment. In the case of the conventional method shown in the upper part of FIG. 7, the sensing data 71 to 71 corresponding to the sensors 1 to 3 that are surely sent at regular intervals, although the data rate of the temperature sensor or the like having a high priority is low in normal times. 73 is guaranteed QoS bandwidth, and can secure a certain amount of data transmission. On the other hand, since the surveillance camera 4 having a high data rate but a low priority is normally transmitted by the best effort communication as much as possible within the transmission range, the data transmission amount varies. Here, when the abnormality of the monitoring target is recognized by the alarm detection and the priority of the monitoring camera data 74 is increased, the QoS bandwidth guarantee is monopolized by the monitoring camera data 74 and the sensor data 72 and 73 having low priority are sent. Will not be able to. Furthermore, if the QoS guaranteed bandwidth is to be expanded only when an alert occurs, the necessary QoS guaranteed bandwidth cannot always be secured depending on the traffic state of the network at that time.

  On the other hand, in the case of the present embodiment shown in the lower part of FIG. 7, as described above, the priority is determined, that is, the priority is determined, and the sensing data 71 and the monitoring camera data are combined with the transmittable band 75. 74, since the compression method of the sensing data 72, 73 is selected, data from all communication terminals can always be transmitted regardless of the traffic state of the network.

  As described above in detail, in the monitoring system of this embodiment, the priority order of data from a plurality of communication terminals is determined according to the status, and the compression method is selected in accordance with the bandwidth that can be transmitted over the network. Therefore, regardless of the traffic state of the network, it is possible to transmit all data from a plurality of communication terminals in the transmission order according to the priority.

  Next, as a second embodiment of the wide area network status estimation processing unit, a case where window size information for flow control by TCP is used will be described.

  In the flow control by TCP, when the data receiving side returns an ACK (Acknowledge) signal notifying that the data has been received to the transmitting side, the window size information is transmitted in accordance with the format of the TCP header. This window size information represents the amount of packets that can be received at one time by the receiving side, that is, the free state of the buffer on the receiving side. When the window size is small, packet congestion is reduced by reducing the amount sent out on the transmission side, and when the window size is large, control is performed to increase throughput by increasing the amount sent out on the transmission side. This window size information does not necessarily match the wide area network situation described in the first embodiment, but can be used as one of the indicators of the wide area network situation, and the network interconnection apparatus shown in FIG. 11 wide area network status estimation processing unit 37 can extract and use window size information in the TCP header.

  Next, as a third embodiment, a configuration example of another communication system of the monitoring system will be described.

  FIG. 15 shows an overall configuration diagram of a monitoring system according to the third embodiment that can realize various types of monitoring. In the figure, the difference from the communication system of FIG. 1 is a three-layer model in the communication system of FIG. 15, and sensors 26 and 27, monitoring cameras 28, and further are added to the edge node 29 of the local area network 14. A monitoring device or the like is connected, and the edge node 29 performs filtering of sensing data and camera data. That is, it can be configured to partially play a role of the filtering processing unit of the network interconnection device 11 in the first and second embodiments.

  Next, a configuration example of a remote monitoring system for plant equipment will be described as a fourth embodiment.

  FIG. 16 shows an overall configuration diagram of a remote monitoring system for plant equipment according to the fourth embodiment. In the figure, the surveillance camera 1 (162) and the surveillance camera 2 (168) voice communication terminal 1 (163) are connected to the network 161 in the plant facility. The network interconnection device 11 performs filtering of camera images and voice data, and is connected to the voice communication terminal 164 and the monitor monitor 165 in the management center 13 via the wide area network 10. The video from the monitoring camera 162 in the plant facility is displayed on the monitoring monitor 165 in the management center. The monitor 167 in the management center 13 can grasp the situation in the plant facility by viewing the video of the monitor monitor 165. The worker 166 in the plant facility can talk to the supervisor 167 in the management center via the voice communication terminal 163 on the plant facility side and the voice communication terminal 165 on the management center side as necessary. Voice communication can be initiated from either the operator 166 or the monitor 167. When it is desired to start voice communication, the worker 166 transmits a voice transmission start request command to the network interconnection device 11 through the voice communication terminal 163. Similarly, the monitor 167 transmits a voice transmission start request command to the network interconnection device 11 through the voice communication terminal 165.

  Also in the fourth embodiment, the processing of the priority order / filter type selection processing unit 37 of the priority control unit 34 is performed as in FIG. In the case of the present embodiment, the event status that is the content of the event detection 41 includes “detection of a voice transmission start request command from the voice communication terminal 163 or 165” or “detection of voice transmission by analyzing a transmission packet”. There are a status when an event related to communication is detected and a status when an event is not detected.

  FIG. 17A and FIG. 17B show an example of a status table used when the sound event is detected. 17A, the status table 171 has compression degree, compression rate, transmission order, and filter type as table components, like the table 53 of FIG. 5A, and is shown corresponding to the compression degrees 1, 2, and 3, respectively. The compression ratio is 1.0, 0.6, 0.4. In the transmission order section, the terminal type 182 and the terminal ID 183 described above with reference to FIG. 18 are specified in order to specify which terminal the data comes from. In the filter type section, the type of processing to be added by the filtering processing unit 33 is specified for the data specified in the transmission order section. In the case of the present embodiment, there are two types of terminals designated in the item of transmission order: “monitoring camera” and “voice communication terminal”. Further, unlike the first embodiment, the terminal ID is assigned to each of the “surveillance cameras” 1 to n and “voice communication terminals” 1 to n, and the terminal types. The table 171 in FIG. 17A assumes a status table in the case where an event relating to the above-described audio is not detected, and the sending order does not depend on the degree of compression, “monitoring cameras” 1 to n, “voice communication terminal”. Specify in the order of 1 to n. For the “voice communication terminal”, “compression” is always designated regardless of the compression type of the filter type. As the filter type of “monitoring camera”, no filtering is specified at the compression level 1, “decimation / reduction / compression” is specified at the compression level 2, and “feature extraction” is specified at the compression level 3 according to the compression level.

  Similarly, the status table 172 in FIG. 17B is assumed to be a status table when an event related to the above-described sound is detected. The difference from the status table 171 in FIG. The point is that the data of the voice communication terminal 1 in which the voice event is detected is preferentially transmitted. Filtering is applied to other transmission data according to the degree of compression selected by the processing flow of FIG.

  According to the fourth embodiment, the network interconnection device 11 determines the priority between the camera image and the sound by detecting the event related to the above-mentioned sound, and the compression degree corresponding to the state of the network in the plant facility and the wide area network. By selecting, voice communication with high call quality is possible regardless of the traffic state of the network.

  INDUSTRIAL APPLICABILITY The present invention is useful as a monitoring system using a sensor or a monitoring camera, and particularly as a monitoring technique for performing priority control in consideration of bandwidth limitation of a broadband network.

DESCRIPTION OF SYMBOLS 10 ... Wide area network 11 ... Network interconnection apparatus 12 ... Communication terminal 13 ... Management center 14 ... Local network 20 ... Monitoring apparatus 21 ... Sensor 1
22 ... Sensor 2
23 ... Sensor 3
24 ... surveillance camera 4
25. Surveillance camera 5
26, 27 ... Sensor 28 ... Camera 29 ... Edge node 31 ... Local network communication processing unit 32 ... Buffering processing unit 33 ... Filtering processing unit 34 ... Priority control unit 35 ... Local network data statistical processing unit 36 ... Wide area network status estimation Processing unit 37 ... Priority order / filter type selection processing unit 38 ... Transmission data selection processing unit 39 ... Wide area network communication processing units 51, 52, 53 ... Status A, B, C tables 61, 62, 171, 172 ... Status Tables 71, 72, 73 ... Sensing data 74 ... Surveillance camera data 75 ... Sendable bandwidth 111, 121 ... Local network communication I / F
112, 122, 132 ... CPU
113123, 133 ... Program storage memory 114, 124, 134 ... Operation memory 115, 135 ... Hardware accelerator 116, 126, 136 ... Wide area network communication I / F
117, 127, 137... Internal bus.
161 ... Network in plant equipment 162, 168 ... Monitoring camera 163, 164 ... Voice communication terminal 165 ... Monitoring monitor 166 ... Worker 167 ... Monitor 180 ... Header information 181 ... Sensing information 182 ... Terminal type 183 ... Terminal ID
184 Time information.

Claims (20)

A monitoring system using a network interconnection device that interconnects a first network to which a plurality of communication terminals are connected and a second network to which a management center is connected,
The network interconnection device selects the transmission data based on the priority order of the transmission data to the management center according to the event status from the plurality of communication terminals, and sets the event status and the communication status of the second network. Select a data compression method of the transmission data according to
Monitoring system characterized by that. The monitoring system according to claim 1,
The plurality of communication terminals include at least one sensor and at least one camera.
Monitoring system characterized by that. The monitoring system according to claim 1,
The network interconnection device is:
A processing unit and a storage unit;
A table for storing the transmission order of the transmission data corresponding to the event status is stored in the storage unit,
The processing unit determines a transmission order of the transmission data based on the table corresponding to the event status.
Monitoring system characterized by that. The monitoring system according to claim 1,
In the network interconnection device,
The communication status of the second network is determined based on the time difference between the transmission time of the transmission data to the second network and the reception time of the transmission data at the management center.
Monitoring system characterized by that. The monitoring system according to claim 1,
The network interconnection device is:
Based on the time difference between the transmission time of the transmission data to the second network and the reception time of the transmission data at the management center, the communication status of the second network determined by the management center is expressed as the management center. Is periodically fed back from
Monitoring system characterized by that. A communication control device that controls to receive data from a plurality of communication terminals via a first network and transmit the data to a management center via a second network,
A communication unit that communicates with each of the first network and the second network, a processing unit, and a storage unit;
The processor is
The event status is extracted by filtering the data from the plurality of communication terminals via the communication unit, the communication status of the second network is estimated,
Select the degree of compression of the data to be sent according to the communication status,
Based on the event status and the degree of compression, a priority order of the data to be transmitted and a compression method are determined.
A communication control device. The communication control device according to claim 6,
The plurality of communication terminals include at least one sensor and at least one camera.
A communication control device. The communication control device according to claim 6,
The storage unit
Corresponding to the event status, storing a table for storing the transmission order of the data to be transmitted,
The processor is
Determining a transmission order of the data to be transmitted based on the table corresponding to the event status;
A communication control device. The communication control device according to claim 6,
The processor is
Determining a communication status of the second network based on a time difference between a transmission time of the data to be transmitted to the second network and a reception time of the data at the management center;
A communication control device. The communication control device according to claim 6,
The processor is
Based on the time difference between the transmission time of the transmission data to the second network and the reception time of the transmission data at the management center, the communication status of the second network determined by the management center is transmitted from the management center. Fed back periodically,
A communication control device. The communication control device according to claim 6,
The processor is
Based on the received data from the management center received via the communication unit, the communication status of the network is estimated.
A communication control device. A communication device communication control method comprising: a communication unit; a processing unit; a storage unit; receiving data from a plurality of communication terminals via a first network; and transmitting the data to a management center via a second network Because
The processor is
Extracting the event status based on the data from the plurality of communication terminals via the communication unit, estimating the communication status of the network,
Select the degree of compression of the data to be sent according to the communication status,
Based on the event status and the degree of compression, a priority order of the data to be transmitted and a compression method are determined.
A communication control method characterized by the above. The communication control method according to claim 12, comprising:
The plurality of communication terminals include at least one sensor and at least one camera.
A communication control method characterized by the above. The communication control method according to claim 12, comprising:
The processor is
Based on the received data from the management center received via the communication unit, the communication status of the network is estimated.
A communication control method characterized by the above. The communication control method according to claim 12, comprising:
The communication status is a communication status of the second network.
A communication control method characterized by the above. The communication control method according to claim 15, comprising:
The processor is
Determining a communication status of the second network based on a time difference between a transmission time of the data to be transmitted to the second network and a reception time of the data at the management center;
A communication control method characterized by the above. The communication control method according to claim 15, comprising:
The processor is
Based on the time difference between the transmission time of the transmission data to the second network and the reception time of the transmission data at the management center, the communication status of the second network determined by the management center is periodically Fed back from the management center,
A communication control method characterized by the above. The monitoring system according to claim 3,
The plurality of communication terminals include at least one voice communication terminal and at least one camera,
The event status includes a status when an event related to voice communication is detected, and a status when it is not detected,
Monitoring system characterized by that. The communication control device according to claim 8,
The plurality of communication terminals include at least one voice communication terminal and at least one camera,
The event status includes a status when an event related to voice communication is detected, and a status when it is not detected,
A communication control device. The communication control method according to claim 13, comprising:
The event status includes a status when an event related to voice communication is detected, and a status when it is not detected,
A communication control method characterized by the above.

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